Turning machines, such as in-turn, mill-turn, and lathes, CNC use tools to carve channels or sections in a rotating part. The tools include a cutting end which, as sharp as it may be, has a rounded portion at its tip. The positioning of the cutting end of the tool determines a position of the channel or section to be removed. In some application, the position of the tool may be required with greater precision before the tool is used. In order to determine the position of the tool, probes, for example mechanical or optical, may be used.
Touch probes typically contact the tool at various locations to determine a position of the tool's cutting end in a plane. A radius of the cutting end's rounded portion is based on nominal values given by the manufacturer of the tool. The nominal values may not correspond enough to the actual radius of the cutting end which could lead to imprecise cutting.
Optical sensors such as laser beam detectors can be used to scan the cutting end of the tool in order to determine its radius. The optical methods are however calculation intensive, and can be sensitive to noise coming from chips of material or thin layers of fluids.